/**
 * Project Name:template-web
 * File Name   :CryptUtil.java
 * Package Name:org.cn.template.component.utils
 * Date:2015年9月27日下午4:18:02
 * Copyright (c) 2015, http://my.oschina.net/httpssl All Rights Reserved.
 *
*/

package org.cn.template.component.utils;

import java.security.SecureRandom;

import javax.crypto.Cipher;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.DESKeySpec;

/**
 * ClassName:CryptUtil <br/>
 * Function :TODO ADD FUNCTION. <br/>
 * Reason	:TODO ADD REASON. <br/>
 * Date     :2015年9月27日 下午4:18:02 <br/>
 * @author  :http://my.oschina.net/httpssl
 * @email   :491835898@QQ.COM
 * @since   :JDK 1.7
 * @see 	 
 */
public class CryptUtil
{
	private final static String DES = "DES";
    /**
     * 加密
     * @param src 数据源
     * @param key 密钥，长度必须是8的倍数
     * @return    返回加密后的数据
     * @throws Exception
     */
    public static byte[] encrypt(byte[] src, byte[] key) throws RuntimeException {
        //      DES算法要求有一个可信任的随机数源
        try{
            SecureRandom sr = new SecureRandom();
            // 从原始密匙数据创建DESKeySpec对象
            DESKeySpec dks = new DESKeySpec(key);
            // 创建一个密匙工厂，然后用它把DESKeySpec转换成
            // 一个SecretKey对象
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
            SecretKey securekey = keyFactory.generateSecret(dks);
            // Cipher对象实际完成加密操作
            Cipher cipher = Cipher.getInstance(DES);
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.ENCRYPT_MODE, securekey, sr);
            // 现在，获取数据并加密
            // 正式执行加密操作
            return cipher.doFinal(src);
        }catch(Exception e){
            throw new RuntimeException(e);
        }
    }
     
    /**
     * 解密
     * @param src   数据源
     * @param key   密钥，长度必须是8的倍数
     * @return      返回解密后的原始数据
     * @throws Exception
     */
    public static byte[] decrypt(byte[] src, byte[] key) throws RuntimeException {
        try{
            //      DES算法要求有一个可信任的随机数源
            SecureRandom sr = new SecureRandom();
            // 从原始密匙数据创建一个DESKeySpec对象
            DESKeySpec dks = new DESKeySpec(key);
            // 创建一个密匙工厂，然后用它把DESKeySpec对象转换成
            // 一个SecretKey对象
            SecretKeyFactory keyFactory = SecretKeyFactory.getInstance(DES);
            SecretKey securekey = keyFactory.generateSecret(dks);
            // Cipher对象实际完成解密操作
            Cipher cipher = Cipher.getInstance(DES);
            // 用密匙初始化Cipher对象
            cipher.init(Cipher.DECRYPT_MODE, securekey, sr);
            // 现在，获取数据并解密
            // 正式执行解密操作
            return cipher.doFinal(src);
        }catch(Exception e){
            throw new RuntimeException(e);
        }
    }
    /**
     * 数据解密
     * @param data
     * @param key 密钥
     * @return
     * @throws Exception
     */
    public final static String decrypt(String data, String key) throws Exception{
        return new String(decrypt(hex2byte(data.getBytes()),key.getBytes()));
    }
    /**
     * 数据加密
     * @param data
     * @param key 密钥
     * @return
     * @throws Exception
     */
    public final static String encrypt(String data, String key){
        if(data!=null)
        try {
            return byte2hex(encrypt(data.getBytes(),key.getBytes()));
        }catch(Exception e) {
            throw new RuntimeException(e);
        }
        return null;
    }
 
    /**
     * 二行制转字符串
     * @param b
     * @return
     */
    private static String byte2hex(byte[] b) {
        StringBuilder hs = new StringBuilder();
        String stmp;
        for (int n = 0; b!=null && n < b.length; n++) {
            stmp = Integer.toHexString(b[n] & 0XFF);
            if (stmp.length() == 1)
                hs.append('0');
            hs.append(stmp);
        }
        return hs.toString().toUpperCase();
    }
     
    private static byte[] hex2byte(byte[] b) {
        if((b.length%2)!=0)
            throw new IllegalArgumentException();
        byte[] b2 = new byte[b.length/2];
        for (int n = 0; n < b.length; n+=2) {
            String item = new String(b,n,2);
            b2[n/2] = (byte)Integer.parseInt(item,16);
        }
        return b2;
    }
}
